GI 275 / G5 redundancy?

[201wantabe]

6 minutes ago, Andy95W said:

That's my actually too many circuit breakers.  The current installation manual (thanks @kpaul) says the GMU should be powered from the G5 HSI breaker, and both GADs share a breaker.

Well that was dumb of me but an easy to fix. That might have also been how my G5 harness as it spelled out what breakers to attach it too.

[Andy95W]

7 minutes ago, 201wantabe said:

Well that was dumb of me but an easy to fix. That might have also been how my G5 harness as it spelled out what breakers to attach it too.

I've been through a few different revisions of the installation manual, it has definitely changed over the years.  For example, less than 2 years ago both G5s were powered by the same bus, but not now.  When you did yours the manual may not have specified.  Having too many breakers certainly doesn't make it wrong.

[donkaye]

On 2/10/2020 at 9:35 AM, RobertGary1 said:

 I don't understand why unless they are having issues with it. Its the cheapest attitude indication you'll ever find.

 

-robert

They are heavy, and fail randomly.  A new one should be purchased every 500 hours for safety and even that many not work for random failures.  As an analogy my plane has the old 2 puck brake system made for the the J Model.  I had to replace the pucks about every 70 hours, but thought that was cheaper than upgrading to the 4 puck system.  As time passed and fuel and labor prices went up, those trips to change the pucks became very expensive.  I upgraded the brake system a few years ago. Getting rid of the vacuum system saves both weight and money in the long run.

[201wantabe]

2 minutes ago, donkaye said:

They are heavy, and fail randomly.  A new one should be purchased every 500 hours for safety and even that many not work for random failures.  As an analogy my plane has the old 2 puck brake system made for the the J Model.  I had to replace the pucks about every 70 hours, but thought that was cheaper than upgrading to the 4 puck system.  As time passed and fuel and labor prices went up, those trips to change the pucks became very expensive.  I upgraded the brake system a few years ago. Getting rid of the vacuum system saves both weight and money in the long run.

Riding myself of the vacuum system allows me to just barely have 1050 pounds useful load in an E model.

[PTK]

I’m curious as to how much weight we are talking about. Does anyone have an idea? In my airplane for example I’d remove: 
KI256, vacuum pump and associated plumbing, KI525A HSI with all the rest of the KCS55A compass system and wiring. 
How much weight would I be losing?

[201wantabe]

23 minutes ago, PTK said:

I’m curious as to how much weight we are talking about. Does anyone have an idea? In my airplane for example I’d remove: 
KI256, vacuum pump and associated plumbing, KI525A HSI with all the rest of the KCS55A compass system and wiring. 
How much weight would I be losing?

For me, the whole PC system, turn coordinator (replaced with a non PC turn coordinator), full vacuum system and pump, AI and DG, as well as the vacuum gauge was a total of 52 pounds. However, your mileage may vary. 

[RobertGary1]

2 hours ago, donkaye said:

They are heavy, and fail randomly.  A new one should be purchased every 500 hours for safety and even that many not work for random failures.  As an analogy my plane has the old 2 puck brake system made for the the J Model.  I had to replace the pucks about every 70 hours, but thought that was cheaper than upgrading to the 4 puck system.  As time passed and fuel and labor prices went up, those trips to change the pucks became very expensive.  I upgraded the brake system a few years ago. Getting rid of the vacuum system saves both weight and money in the long run.

I was referring to an alternative of just removing them. I see no reason to remove my vacuum attitude Instrument, just move it off to the side of my 275’s. As a backup attitude vacuum is pretty inexpensive. 
 

-Robert 

[EricJ]

5 hours ago, 201wantabe said:

Actually the battery is the same size, the GI-275 is just far more power intensive. 

If that's true I wonder what they do with all that additional power consumption.   It's a smaller display, the computing requirements don't seem much higher, etc.

 

[RobertGary1]

2 hours ago, EricJ said:

If that's true I wonder what they do with all that additional power consumption.   It's a smaller display, the computing requirements don't seem much higher, etc.

 

Yea, I'm skeptical too. I think its because the 275 is certified from day one including class 3 jets etc. I bet if you put the two next to each other the battery would last about the same.

 

-Robert